JP3845188B2 - Automatic vehicle steering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To interrupt an automatic steering control without giving a sense of incompatibility to a driver when the driver has conducted a steering operation during the automatic steering control. SOLUTION: In accordance with increase of the steering torque T by the steering motion of a driver from the first set torque T1 to the fourth set torque T4, the first to fourth set times ts1 -ts4 corresponding to the first to fourth set torque T1-T4 decrease. When a steering torque T exceeding the first to fourth set torques T1-T4 is sensed for a time over the respective set times ts1 -ts4 , judgement is passed that the driver has conducted a steering operation, and the automatic steering control is interrupted. E in the illustration exhibits the case in which the automatic steering operation is interrupted in compliance with sensing of a steering torque T exceeding a third set torque T3 for a time over a third set time ts3 .

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic vehicle steering apparatus for automatically parking a vehicle without depending on a driver's steering operation.
[0002]
[Prior art]
Such automatic steering devices for vehicles are already known from Japanese Patent Application Laid-Open Nos. 3-74256 and 4-55168. These automatic steering devices for vehicles use an actuator of a conventionally well-known electric power steering device, and control the actuator based on the relationship between the movement distance of the vehicle stored in advance and the turning angle, thereby allowing back parking and Parallel parking is performed automatically.
[0003]
[Problems to be solved by the invention]
By the way, in the conventional system, when the driver operates the steering wheel during the automatic steering control and it is determined that the steering torque exceeds a predetermined value, the automatic steering control is stopped.
[0004]
However, if the determination is made only by comparing the output of the steering torque detection means with a predetermined value, the steering torque detection means may cause noise, or the tire may be stepped on a pebble, or if the actuator is automatically steered. Due to the inertia torque of the steering wheel, the output of the steering torque detecting means may temporarily exceed a predetermined value, and the automatic steering control is stopped each time. If the predetermined value is set high to avoid such inconvenience, not only does the automatic steering and the manual steering interfere with each other, but the driver feels uncomfortable, and the driver operates the steering wheel during the automatic steering control. However, the automatic steering control may not be stopped immediately.
[0005]
Thus, it is conceivable that when a steering torque of a predetermined value or more is detected for a predetermined time or more, it is determined that manual steering has been performed and automatic steering control is stopped. In this case, when the driver performs gentle manual steering and the steering torque slightly exceeds a predetermined value, the automatic steering control is stopped after a predetermined time without giving the driver a sense of incongruity. However, when the driver performs a sharp manual steering and the steering torque greatly exceeds a predetermined value, the automatic steering control is not stopped until the predetermined time elapses, so that the steering wheel becomes heavy and the driver feels uncomfortable. Sometimes.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to stop automatic steering control without causing the driver to feel uncomfortable when the driver performs a steering operation during automatic steering control.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is directed to a movement trajectory setting means for storing or calculating a movement trajectory of a vehicle to a target position, an actuator for turning a wheel, and a driver on a steering wheel. The driving torque of the actuator is controlled based on the steering torque detecting means for detecting the applied steering torque and the movement trajectory set by the movement trajectory setting means, and a steering torque of a predetermined value or more set over a predetermined time or more. In a vehicle automatic steering apparatus comprising an actuator control means for stopping the control of the actuator based on the movement trajectory when detected, a plurality of types of the predetermined values are set, and the predetermined values are set corresponding to the predetermined values. The predetermined time is changed.
[0008]
According to the above configuration, even when the output of the steering torque detecting means temporarily increases due to noise or an inertia torque generated when the tire steps on a pebble, the state where the steering torque is not less than a predetermined value is predetermined. As long as the control means does not continue over a period of time, the control means does not stop the control of the actuator based on the movement locus, so there is no possibility that the automatic steering control is stopped against the driver's intention. In addition, a plurality of types of the predetermined values are set, and the predetermined time is changed corresponding to each predetermined value, so that the timing at which the automatic steering control is stopped is changed according to the magnitude of the steering torque applied by the driver. Thus, the automatic steering control can be accurately stopped without causing the driver to feel uncomfortable.
[0009]
The predetermined value is set to 0.2 kgfm, 0.4 kgfm, 0.6 kgfm, and 0.8 kgfm in the embodiment, and the predetermined time is 0.12 sec, 0.08 sec, 0.06 sec, 0 in the first embodiment. .05 sec and 0.12 sec, 0.10 sec, 0.09 sec, 0.85 sec in the second embodiment, these values are design values that can be changed as appropriate.
[0010]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, the predetermined time decreases as the predetermined value increases.
[0011]
According to the above configuration, when the driver performs a sharp steering operation, the automatic steering control is immediately stopped, so the driver does not feel uncomfortable, and even when the driver performs a gentle steering operation, The automatic steering control can be stopped by continuing the state for a predetermined time.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.
[0013]
1 to 9 show a first embodiment of the present invention. FIG. 1 is an overall configuration diagram of a vehicle equipped with a steering control device, FIG. 2 is an explanatory diagram of the operation of a back parking / left mode, and FIG. FIG. 4 is a graph showing a steering torque and an inertia torque by a steering operation, FIG. 5 is a graph showing a steering torque when a gentle steering operation is performed, and FIG. 6 is a set torque. FIG. 7 is a graph illustrating the relationship between the set torque and the set time, and FIGS. 8 and 9 are graphs illustrating the operation.
[0014]
As shown in FIG. 1, the vehicle V includes a pair of front wheels Wf, Wf and a pair of rear wheels Wr, Wr. A steering wheel 1 and front wheels Wf and Wf which are steering wheels are rotated integrally with the steering wheel 1, a pinion 3 provided at the lower end of the steering shaft 2, a rack 4 meshing with the pinion 3, and a rack 4 Are connected by left and right tie rods 5, 5 provided at both ends, and left and right knuckles 6, 6 connected to tie rods 5, 5. A steering actuator 7 made of an electric motor is connected to the steering shaft 2 via a worm gear mechanism 8 in order to assist the operation of the steering wheel 1 by the driver or to perform automatic steering for garage entry, which will be described later.
[0015]
The steering control device 21 includes a control unit 22 and a storage unit 23, and the control unit 22 detects a turning angle that detects the turning angle θ of the front wheels Wf and Wf based on the rotation angle of the steering wheel 1. a means S _1, the steering torque detecting means S ₂ for detecting a steering torque T of the steering wheel 1, the left and right front wheels Wf, a front wheel rotational angle detecting means S _3, S ₃ for detecting the rotation angle of Wf, the brake pedal 9 The brake operation amount detection means S ₄ for detecting the operation amount of the shift and the shift for detecting the shift range (“D” range, “R” range, “N” range, “P” range, etc.) selected by the select lever 10. Signals from the range detection means S ₅ and a total of eight object detection means S ₆ provided at the front, center and rear of the vehicle V are input. The object detection means S ₆ is composed of a known sonar, radar, TV camera and the like. The lines connecting the eight object detection means S ₆ ... And the control unit 22 are omitted in order to prevent complication of the drawing. The control unit 22 constitutes the actuator control means of the present invention, and the storage unit 23 constitutes the movement trajectory setting means of the present invention.
[0016]
As is clear from FIG. 3, the mode selection switch S ₇ and the automatic parking start switch S ₈ operated by the driver are connected to the control unit 22. Mode selecting switch S ₇ is operated to select later-described four types of parking mode, i.e. reverse parking / right mode, reverse parking / left mode, one of the parallel parking / right mode and parallel parking / left mode 4 buttons are provided. Automatic parking start switch S ₈ is operated to start automatic parking according to any of the mode selected by the mode selection switch S _7.
[0017]
In the storage unit 23, the data of the four types of parking modes, that is, the relationship of the reference turning angle θref with respect to the movement distance X of the vehicle V is stored in advance as a table. The moving distance X of the vehicle V is obtained by multiplying the known circumference of the front wheel Wf by the rotation angle of the front wheel Wf detected by the front wheel rotation angle detection means S ₃ and S ₃ . For calculating the movement distance X, the high select value, low select value, or average value of the outputs of the pair of left and right front wheel rotation angle detecting means S ₃ and S ₃ is used.
[0018]
Based on the signals from the detection means S _{1 to} S ₆ and the switches S ₇ and S ₈ and the parking mode data stored in the storage unit 23, the control unit 22 operates the steering actuator 7; It controls the operation of the operation stage teaching device 11 including a liquid crystal monitor, a speaker, a lamp, a chime, a buzzer, and the like.
[0019]
Next, the operation of the embodiment of the present invention having the above-described configuration will be described.
[0020]
The normal time when not used to automatically parking (when the mode selecting switch S ₇ is not operated), the steering control apparatus 21 functions as a general power steering control unit. Specifically, when the driver operates the steering wheel 1 to turn the vehicle V, the steering torque detection means S ₂ detects the steering torque T input to the steering wheel 1, and the control unit 22 determines the steering torque T. Based on this, the driving of the steering actuator 7 is controlled. As a result, the left and right front wheels Wf and Wf are steered by the driving force of the steering actuator 7, and the driver's steering operation is assisted.
[0021]
Next, the content of the automatic steering control will be described by taking the back parking / left mode (a mode in which the vehicle is parked while backing to the parking position on the left side of the vehicle V) as an example.
[0022]
First, as shown in FIG. 2 (A), the vehicle V is moved to the vicinity of the garage to be parked by the driver's own steering operation, and is determined in advance with the left side of the vehicle body as close as possible to the garage entrance line. The vehicle V is stopped at a position (start position {circle around (1)}) where the reference (for example, a mark or side mirror provided inside the door) coincides with the center line of the garage. Then, ON the automatic parking start switch S ₈ with to select the back parking / left mode by operating the mode selection switch S ₇ Then, the automatic steering control is started. While the automatic steering control is being performed, the operation stage teaching device 11 switches the current position of the own vehicle, surrounding obstacles, the parking position, the predicted movement trajectory of the own vehicle from the start position to the target position, and switching from forward to reverse. The turn-back position and the like are displayed, and various instructions and warnings such as operation of the select lever 10 at the turn-back position are given to the driver by sound from the speaker.
[0023]
The automatic steering control, the driver based on data alone without operating the steering wheel 1, reverse parking / left mode selected by the mode selection switch S ₇ is creeping vehicle V loosen the brake pedal 9 The front wheels Wf, Wf are automatically steered. That is, while the vehicle V moves forward from the start position {circle over (1)} to the turning position {circle around (2)}, the front wheels Wf and Wf are automatically steered to the right, while the vehicle V moves backward from the turning position {circle around (2)} to the target position {circle around (3)} The front wheels Wf, Wf are automatically steered to the left.
[0024]
As apparent from FIG. 2 (B), during automatic steering, the control unit 22 reads the back parking / left mode reference turning angle θref read from the storage unit 23 and the turning angle detection means S _1. The deviation E (= θref−θ) is calculated on the basis of the turning angle θ input from, and the operation of the steering actuator 7 is controlled so that the deviation E becomes zero. At this time, since the data of the reference turning angle θref is set corresponding to the moving distance X of the vehicle V, the vehicle V always moves on the moving locus even if there is a slight fluctuation in the vehicle speed of the creep travel. It will be.
[0025]
By the way, since the automatic steering control is executed while the driver steps on the brake pedal 9 and the vehicle creeps, when the driver finds an obstacle, the driver quickly depresses the brake pedal 9 to stop the vehicle V. Can do.
[0026]
If the automatic steering control described above, the driver but is released when OFF the mode selecting switch S _7, if the driver also has otherwise takes his foot from the brake pedal 9, the driver operates the steering wheel 1, either the object detecting means S ₆ is released if an obstacle is detected, to return to normal power steering control.
[0027]
The stop of the automatic steering control when the driver operates the steering wheel 1 will be further described. If the driver during the automatic steering control has been discovered an obstacle, or when the driver operates the steering wheel 1 when an attempt is made to modify the course at their own will, the steering torque steering torque detecting means S ₂ is due to a steering operation of the driver When T is detected, the control unit 22 stops the automatic steering control. As a result, interference between automatic steering and steering by the driver's operation can be avoided, and obstacle avoidance can be achieved quickly, and there is no need to perform a special switch operation to stop automatic steering control. Improves.
[0028]
By the way, the output of the steering torque detecting means S ₂ does not necessarily represent the steering torque T generated by the driver's steering operation. If the output of the steering torque detecting means S ₂ increases momentarily due to noise or the like, The impact of stepping on the curb is transmitted to the steering shaft, the rotation of the steering wheel 1 stops suddenly at the end of the rack 4, or the steering actuator 7 is actuated to simulate the inertia of the steering wheel 1. Do steering torque T (hereinafter, referred to as inertia torque) is detected, there are cases where the output of the steering torque detecting means S ₂ is increased instantaneously. Therefore, it is necessary to discriminate the steering torque T due to the driver's steering operation and the steering torque T due to other factors, and to stop the automatic steering control only when the steering torque T due to the driver's steering operation is detected. .
[0029]
As shown by a solid line in FIG. 4, the output of the steering torque detecting means S _{2 in} response to the driver's steering operation input is generally stepped. On the other hand, as shown by a broken line in FIG. 4, inertia generated by an impact when the tire steps on a pebble or a curb or when the rotation of the steering wheel 1 stops suddenly at the end of the end of the rack 4. the output of the steering torque detecting means S ₂ for the torque becomes impulsive. Therefore, if it is determined that the steering operation by the driver is performed when the steering torque T equal to or greater than the set torque Ts (for example, 0.2 kgfm) is detected over the set time ts (for example, 0.2 sec), The steering operation by the driver and the inertia torque can be identified.
[0030]
By the way, as shown in FIG. 5, when a steering torque T slightly exceeding the set torque Ts is input beyond the set time ts by the steering operation by the driver, the automatic steering control is stopped without giving the driver a sense of incongruity. be able to. However, as shown by the solid line in FIG. 4, when the driver inputs a large steering torque T that greatly exceeds the set torque Ts, the automatic steering control is not stopped unless the large steering torque T is input over the set time ts. As a result, the driver feels uncomfortable.
[0031]
If the set time ts is shortened to avoid such a problem, the steering operation by the driver and the inertia torque cannot be identified, and the automatic steering control may be stopped by the inertia torque. As will be described later, when the set torque Ts is increased, the set time t can be shortened. However, in order to stop the automatic steering control, the driver must input a large steering torque T in any case. There is.
[0032]
Therefore, as shown in FIG. 6, a plurality of different set torques T1 to T4 are provided, and for example, the first set time ts ₁ is set to ts ₁ = t ₁ −t ₀₁ + dt with respect to the first set torque T1. . Here, dt is a margin for reliably identifying the steering operation by the driver and the inertia torque. Similarly, the second set time ts ₂ is set by ts ₂ = t ₂ −t ₀₂ + dt for the second set torque T2, and the third set time ts ₃ is set by ts ₂ for the third set torque T3. By setting ₃ = t ₃ −t ₀₃ + dt and setting the fourth set time ts ₄ with respect to the fourth set torque T4 by ts ₄ = t ₄ −t ₀₄ + dt, as shown in FIG. with respect to the fourth set torque T1-T4, the first to fourth setting time decreases according to their increasing ts ₁ ~ts ₄ is set.
[0033]
In the embodiment, the first to fourth set torques T1 to T4 are set to 0.2 kgfm, 0.4 kgfm, 0.6 kgfm, and 0.8 kgfm, respectively, and the first to fourth set times ts _{1 to} ts ₄ are each 0. .12 sec, 0.08 sec, 0.06 sec, and 0.05 sec. The margin dt is set to 20 msec.
[0034]
Next, the process from when the driver performs the steering operation until the automatic steering control ends will be described with reference to FIGS.
[0035]
When the steering torque T driver during the automatic steering control is performed steering operation is equal to or greater than the first predetermined torque T1, the state starts counting to time to determine whether to continue the first set time ts ₁ or more (See FIG. 8A). When the steering torque T is further increased second set torque T2 or more, in its state starts counting to time to determine whether or not to continue the second set time ts ₂ or more (see FIG. 8 (B) refer) . Similarly, when the steering torque T further increases and becomes equal to or greater than the third set torque T3 or the fourth set torque T4, whether or not the state continues for the third set time ts ₃ or the fourth set time ts ₄ or more. Is started to count (see FIG. 8C).
[0036]
As shown in FIG. 9D, if the steering torque T starts to decrease past the peak and becomes less than the fourth set torque T4 before the fourth set time ts ₄ elapses, the fourth set is set at that time. The count of the time ts ₄ is stopped, and the stop of the automatic steering control is not executed here. At this time, since the steering torque T is still more than the first to third set torques T1 to T3, the counting of the _first to third set times ts _{1 to} ts ₃ is continued. For example, as shown in FIG. 9E, if the steering torque T is still equal to or greater than the third steering torque T3 when the third set time ts ₃ has elapsed, it is determined that the driver has performed the steering operation and automatic steering is performed. Stop control.
[0037]
Thus, when a large steering torque T is generated when the driver performs an abrupt steering operation, the automatic steering control is stopped even if the steering torque T continues only for a short time, and the driver may feel uncomfortable. Disappear. Moreover, even if the driver performs a gentle steering operation and a small steering torque T is generated, the automatic steering control is stopped if the state where the steering torque T exceeds the first set torque T1 continues for a predetermined time ts ₁ . When not in an emergency, the automatic steering control can be stopped without applying a large steering torque T.
[0038]
Next, a second embodiment of the present invention will be described with reference to FIG.
[0039]
In the second embodiment, when the detected steering torque T becomes equal to or greater than the first set torque T1, the first set time ts ₁ is set and time counting is started, and the steering torque T is equal to or greater than the first set torque T1. During this time, counting continues, and when the first set time ts ₁ elapses, it is determined that the driver has performed a steering operation, and automatic steering control is stopped. When the first set time steering torque T during the counting of ts ₁ is equal to or greater than the second set torque T2, the first set time ts ₁ is dimensional worlds the second set time Ts ₂ shorter than the second set torque T2 or higher When the steering torque T continues until the second set time Ts ₂ elapses, it is determined that the driver has performed the steering operation, and the automatic steering control is stopped. Similarly, when the steering torque T becomes equal to or greater than the third set torque T3 or the fourth set torque T4, the second set time Ts ₂ is changed to the third set time Ts ₃ or the fourth set time Ts ₄ shorter than that, When the steering torque T equal to or greater than the third set torque T3 or the fourth set torque T4 continues until the third set time Ts ₃ or the fourth set time Ts ₄ elapses, it is determined that the driver has performed the steering operation and automatic steering control is performed. Cancel.
[0040]
In the present embodiment, the first to fourth set times ts _{1 to} ts ₄ are set to 0.12 sec, 0.10 sec, 0.09 sec, and 0.085 sec, respectively.
[0041]
Also according to the second embodiment, the same effects as those of the first embodiment described above can be obtained.
[0042]
Although the embodiments of the present invention have been described above, various design changes can be made without departing from the scope of the present invention.
[0043]
For example, in the embodiment, the movement locus of the vehicle V to the target position is stored in the storage unit 23 in advance, but the movement locus can be calculated from the current position and the target position of the vehicle V.
[0044]
【The invention's effect】
As described above, according to the first aspect of the present invention, even if the output of the steering torque detecting means temporarily increases due to noise or inertia torque generated when the tire steps on a pebble, Since the actuator control means does not stop the actuator control based on the movement trajectory unless the state where the steering torque is not less than a predetermined value continues for a predetermined time or more, there is a possibility that the automatic steering control is stopped against the driver's intention. Absent. In addition, a plurality of types of the predetermined values are set, and the predetermined time is changed corresponding to each predetermined value, so that the timing at which the automatic steering control is stopped is changed according to the magnitude of the steering torque applied by the driver. Thus, the automatic steering control can be accurately stopped without causing the driver to feel uncomfortable.
[0045]
According to the second aspect of the present invention, when the driver performs an abrupt steering operation, the automatic steering control is immediately stopped, so that the driver does not feel uncomfortable, and the driver has a gentle steering. Even when the operation is performed, the automatic steering control can be stopped by continuing the state for a predetermined time.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a vehicle equipped with a steering control device. FIG. 2 is an explanatory diagram of the operation of a back parking / left mode. FIG. 3 is a diagram showing a mode selection switch and an automatic parking start switch. Graph showing steering torque and inertia torque FIG. 5 is a graph showing steering torque when a gentle steering operation is performed. FIG. 6 is a graph explaining a method for setting a set time from a set torque. FIG. 8 is a graph for explaining the operation. FIG. 9 is a graph for explaining the operation. FIG. 10 is a graph corresponding to FIG. 6 according to the second embodiment of the invention. Explanation of]
1 Steering wheel 7 Steering actuator (actuator)
22 Control unit (actuator control means)
23 storage unit (movement trajectory setting means)
S ₂ Steering torque detection means T Steering torque T1 to T4 Predetermined values ts _{1 to} ts ₄ Predetermined time V Vehicle Wf Front wheel (wheel)

Claims (2)

Movement trajectory setting means (23) for storing or calculating the movement trajectory of the vehicle to the target position;
An actuator (7) for steering the wheel (Wf);
Steering torque detection means (S ₂ ) for detecting the steering torque (T) applied by the driver to the steering wheel (1);
The drive of the actuator (7) is controlled based on the movement locus set by the movement locus setting means (23), and the steering torque (T) equal to or greater than a predetermined value (T1 to T4) set in advance is set for a predetermined time (ts). _{1 to} ts ₄ ) actuator control means (22) for stopping the control of the actuator (7) based on the movement trajectory when detected over the above,
In an automatic steering device for a vehicle equipped with
The predetermined value (T1-T4) are a plurality of types set, the vehicle, characterized in that the predetermined time corresponding to each of a predetermined value _{(T1~T4) (ts 1 ~ts 4} ) is changed Automatic steering device. The automatic steering apparatus for a vehicle according to claim 1, wherein the predetermined time (ts _{1 to} ts ₄ ) decreases with an increase in the predetermined value (T1 to T4).

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